1. Field of the Invention
The present invention relates to an illuminating device and a tube-like lamp thereof, and more specifically relates to a backlight device for a liquid crystal display.
2. Description of the Related Art
Generally, a liquid crystal display includes a liquid crystal panel which has two substrates and a liquid crystal interposed therebetwveen, and an illuminating device such as a backlight unit which is disposed behind the liquid crystal panel. The backlight unit is configured to distribute a light from a light source uniformly over the surface of the liquid crystal panel. Currently, there are a few kinds of backlight units such as direct and edge light types.
The direct type backlight device usually comprises a U shaped lamp disposed inside a housing. The U shaped lamp has two terminal portions adapted for electrically connecting to a power source. Since the terminal portions of the U shaped lamp are located on the same side, the direct type backlight device is typically provided with a fixing mechanism such as a rubber fastener for securely attaching the bending portion of the U shaped lamp to the housing. It is noted that the conventional fastener is typically configured to directly wrap around a part of the bending portion of the U shaped lamp thereby further immobilizing the lamp.
Since the rubber fastener directly wraps around the U shaped lamp, the rubber fastener facilitates the heat dissipation from the bending portion of the U shaped lamp. Therefore, when a liquid crystal display using the aforementioned backlight device is placed in a low temperature environment (such as a 0xc2x0 C. chamber) for conducting a long-time operation test, the temperature of the bending portion of the U shaped lamp is at least 10 degrees Centigrade lower than that of other portions of the lamp thereby causing the phenomenon of low-temperature pink.
Therefore, it is an object of the present invention to provide an illuminating device characterized by utilizing a novel fixing mechanism to facilitate the immobilization of tube-like lamps provided therein which overcomes, or at least reduces the above-mentioned problems of the prior art.
According to one embodiment of the present invention, the illuminating device mainly includes a tube-like lamp disposed in a main body. The tube-like lamp has two terminal portions adapted for electrically connecting to a power source and a bending portion between the terminal portions. The tube-like lamp is characterized by having a buffer part, e.g., an O-ring or a C-shaped ring, securely attached on the bending portion for lessening or absorbing the shock of an impact on the tube-like lamp. The main body is provided with a supporting device for engaging the buffer part of the tube-like lamp thereby helping to immobilize the tube-like lamp. Specifically, the supporting device has two hooked portions and a gap between the hooked portions. The hooked portions are configured to support the tube-like lamp, and the buffer part of the tube-like lamp fits with sufficient tightness into the gap between the hooked portions thereby immobilizing the lamp efficiently. The main body typically includes a housing, a reflector interposed between the tube-like lamp and the housing, and a diffusion plate. Specifically, the housing of the main body includes a base and a case body disposed on the base. The reflector is provided between the tube-like lamp and the base of the housing. The diffusion plate seals the top of the case body of the housing. The terminal portions of the tube-like lamp are disposed along one side of the base of the housing.
The illuminating device according to another embodiment of the present invention is characterized in that the main body is provided with a first supporting device having two hooked portions configured to support a first tube-like lamp thereby helping to immobilize the first tube-like lamp. The illuminating device is preferably provided with a second tube-like lamp, a second supporting device having two hooked portions configured to support the second tube-like lamp, and a third supporting device disposed on the main body and disposed between the first tube-like lamp and the second tube-like lamp wherein the third supporting device having two hooked portions configured to support the first tube-like lamp and the second tube-like lamp.
The fixing mechanism of the present invention, i.e., the supporting device, is characterized by utilizing two hooked portions to support the tube-like lamp thereby significantly reducing the heat dissipated from the contact surface between the lamp and the fixing mechanism. Therefore, the phenomenon of low-temperature pink is not observed when a liquid crystal display using the backlight device of the present invention is placed in a low temperature environment (such as a 0xc2x0 C. chamber) for conducting a long-time operation test.